Hand-foot-and-mouth disease (HFMD) spreads through direct contact with an infected person’s saliva, nasal mucus, blister fluid, or stool. The viruses responsible are surprisingly hardy and can travel through several different routes, which is why outbreaks move so quickly through daycare centers and households with young children.
The Viruses Behind It
HFMD is caused by a group of viruses called enteroviruses. In the United States, coxsackievirus A16 is the most common culprit. Coxsackievirus A6 also causes cases and tends to produce more severe symptoms. In East and Southeast Asia, enterovirus 71 (EV-A71) drives many outbreaks and, in rare cases, can lead to serious complications like brain swelling.
Because multiple virus strains cause the same illness, you can get HFMD more than once. Recovering from one strain gives you immunity to that specific strain, but a different one can still infect you. This is why some children seem to catch it repeatedly, especially before age 5 when their immune systems are still encountering these viruses for the first time.
How the Virus Spreads
There are three main transmission routes, and all of them come down to body fluids making contact with your mouth, nose, or eyes.
- Respiratory droplets. Coughing, sneezing, and even talking can launch virus-containing droplets into the air at close range. This is the most common route during the early days of illness, when cold-like symptoms are at their peak.
- Blister fluid. The small blisters on the hands, feet, and mouth contain live virus. If a child pops a blister and then touches a toy, doorknob, or another person, the virus transfers easily.
- Fecal-oral contact. The virus sheds in stool for weeks after symptoms clear. Diaper changes, shared bathrooms, and imperfect handwashing are the usual culprits here, particularly in daycare settings.
You can also pick up the virus by touching a contaminated surface and then touching your face. Shared cups, utensils, and towels are common bridges between an infected person and a new host.
How Long the Virus Lives on Surfaces
The viruses behind HFMD don’t survive indefinitely on dry surfaces, but they last long enough to matter. Research on coxsackievirus A16 and enterovirus 71 found that infectivity drops sharply within a few hours on most materials. On plastic, coxsackievirus A16 loses about 80% of its ability to cause infection after just 3 hours. It holds up better on wood and stainless steel, staying above 50% infectivity after 4 hours. Enterovirus 71 can remain infectious on wood for up to 7 hours.
One important detail: while the live virus dies off relatively fast, viral genetic material (RNA) can linger on dry surfaces for up to 28 days. That doesn’t necessarily mean the surface is still contagious, but it does explain why standard cleaning alone may not eliminate every trace. If someone in your household is sick, cleaning surfaces with soap and water first, then disinfecting with a diluted bleach solution (about 1/3 cup of regular unscented bleach per gallon of water), is the most effective approach. Leave the solution on the surface for at least one minute before wiping, and mix a fresh batch each day since diluted bleach loses potency after 24 hours.
When Someone Is Most Contagious
A person with HFMD is most contagious during the first week of illness, when symptoms are active and blisters haven’t yet dried out. But infectiousness doesn’t end when the rash fades. The virus continues to shed in stool for days to weeks after a person feels completely better, which makes it possible to spread the illness even after returning to school or work.
The incubation period, the gap between catching the virus and feeling sick, typically runs 3 to 7 days, with a median around 4 to 5 days for young children. Some cases take up to 10 days to show symptoms. During this window a person may already be shedding virus without knowing they’re infected, which is one reason outbreaks are so hard to contain.
Who Gets It and Where
Children under 5 are by far the most common targets. Their immune systems haven’t built up defenses against the enteroviruses yet, and the environments they spend time in (daycare centers, preschools, playgroups) involve constant sharing of toys, surfaces, and close physical contact. HFMD spreads quickly in these settings.
Adults can absolutely get HFMD too, though they’re less likely to develop the full set of symptoms. Parents and caregivers who change diapers or clean up after sick children are at the highest risk. Pregnant women, older adults, and people with weakened immune systems may experience more significant illness if infected.
Outbreaks peak in summer and early fall in temperate climates. Warm, humid conditions help enteroviruses survive longer outside the body, and children tend to be in closer quarters at camps and childcare programs during these months.
Reducing Your Risk
There is no vaccine available for the strains circulating in the United States. Prevention comes down to hygiene, especially handwashing. Washing your hands with soap and water for at least 20 seconds after diaper changes, bathroom visits, and before preparing food is the single most effective measure.
If someone in your household is sick, avoid sharing cups, utensils, and towels. Clean frequently touched surfaces daily with soap and water, followed by a bleach-based disinfectant. Pay extra attention to toys, since young children put them in their mouths constantly. Plastic toys can be washed in soapy water and wiped with dilute bleach. Soft toys and stuffed animals are harder to disinfect and may need to be kept away from the sick child during the illness.
Keeping a sick child home from daycare while they have a fever or open blisters reduces the chance of spreading the virus to classmates, though it won’t eliminate the risk entirely given that viral shedding continues after symptoms resolve.